Since the liquid crystal itself does not emit light, a back light module (BLM) is generally used in the liquid crystal display (LCD) for providing uniform light source for the liquid crystal screen, so as to realize image display. Based on different arrangement positions of the light source in the back light module, the back light module is classified into side type back light module and direct type back light module, wherein the light source in the side type back light module is located at the side of the display panel, the light source in the direct type back light module is located at the bottom of the display panel.
The existing back light module generally uses a light emitting diode (LED) as the light source, the LED is a low heat luminous body, however, a large amount of LEDs that are lit up for a long time will also generate a lot of heat; meanwhile, for the convenience of power supply connection, a printed circuit board (PCB) for supplying power and signal source driving for the liquid crystal screen in the display panel is connected with the liquid crystal screen and is arranged on the back plate, during operation of the display device, the PCB will also generate certain heat. In order to ensure normal operation of the display device, heat dissipation holes are generally provided on the shell at the back of the display device, and the light source and the PCT are arranged in a heat dissipation chamber formed between the back plate and the shell.
In order to enable the structure of the display device to be thin, in the existing side type back light module, the heat generated by the light source and the heat generated by the PCB are collected simultaneously and conducted through a same heat dissipation plate, and the back plate under the light bar supports the PCB directly. Since the heat dissipation plate does not distinguish the heat emanated by the light bar and the PCB, and generally the heat emanated by the light bar is greater than the heat emanated by the PCB, the heat that is directly conducted to the back plate will cause the PCB located at the back plate to have a relatively large heat dissipation pressure, which accelerates aging of the PCB and the electronic components thereon, and reduces the use lifetime of the display device.
It shows that designing a back light module that can increase the heat dissipating effect and prevent aging of the PCB and the electronic components thereon on the basis of ensuring a compact structure has become a technical problem that needs to be solved urgently at present.